| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * Asm versions of Xen pv-ops, suitable for direct use. |
| * |
| * We only bother with direct forms (ie, vcpu in percpu data) of the |
| * operations here; the indirect forms are better handled in C. |
| */ |
| |
| #include <asm/errno.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/percpu.h> |
| #include <asm/processor-flags.h> |
| #include <asm/segment.h> |
| #include <asm/thread_info.h> |
| #include <asm/asm.h> |
| #include <asm/frame.h> |
| #include <asm/unwind_hints.h> |
| |
| #include <xen/interface/xen.h> |
| |
| #include <linux/init.h> |
| #include <linux/linkage.h> |
| #include <../entry/calling.h> |
| |
| .pushsection .noinstr.text, "ax" |
| /* |
| * Disabling events is simply a matter of making the event mask |
| * non-zero. |
| */ |
| SYM_FUNC_START(xen_irq_disable_direct) |
| movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask |
| RET |
| SYM_FUNC_END(xen_irq_disable_direct) |
| |
| /* |
| * Force an event check by making a hypercall, but preserve regs |
| * before making the call. |
| */ |
| SYM_FUNC_START(check_events) |
| FRAME_BEGIN |
| push %rax |
| push %rcx |
| push %rdx |
| push %rsi |
| push %rdi |
| push %r8 |
| push %r9 |
| push %r10 |
| push %r11 |
| call xen_force_evtchn_callback |
| pop %r11 |
| pop %r10 |
| pop %r9 |
| pop %r8 |
| pop %rdi |
| pop %rsi |
| pop %rdx |
| pop %rcx |
| pop %rax |
| FRAME_END |
| RET |
| SYM_FUNC_END(check_events) |
| |
| /* |
| * Enable events. This clears the event mask and tests the pending |
| * event status with one and operation. If there are pending events, |
| * then enter the hypervisor to get them handled. |
| */ |
| SYM_FUNC_START(xen_irq_enable_direct) |
| FRAME_BEGIN |
| /* Unmask events */ |
| movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask |
| |
| /* |
| * Preempt here doesn't matter because that will deal with any |
| * pending interrupts. The pending check may end up being run |
| * on the wrong CPU, but that doesn't hurt. |
| */ |
| |
| /* Test for pending */ |
| testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending |
| jz 1f |
| |
| call check_events |
| 1: |
| FRAME_END |
| RET |
| SYM_FUNC_END(xen_irq_enable_direct) |
| |
| /* |
| * (xen_)save_fl is used to get the current interrupt enable status. |
| * Callers expect the status to be in X86_EFLAGS_IF, and other bits |
| * may be set in the return value. We take advantage of this by |
| * making sure that X86_EFLAGS_IF has the right value (and other bits |
| * in that byte are 0), but other bits in the return value are |
| * undefined. We need to toggle the state of the bit, because Xen and |
| * x86 use opposite senses (mask vs enable). |
| */ |
| SYM_FUNC_START(xen_save_fl_direct) |
| testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask |
| setz %ah |
| addb %ah, %ah |
| RET |
| SYM_FUNC_END(xen_save_fl_direct) |
| |
| SYM_FUNC_START(xen_read_cr2) |
| FRAME_BEGIN |
| _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX |
| _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX |
| FRAME_END |
| RET |
| SYM_FUNC_END(xen_read_cr2); |
| |
| SYM_FUNC_START(xen_read_cr2_direct) |
| FRAME_BEGIN |
| _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX |
| FRAME_END |
| RET |
| SYM_FUNC_END(xen_read_cr2_direct); |
| .popsection |
| |
| .macro xen_pv_trap name |
| SYM_CODE_START(xen_\name) |
| UNWIND_HINT_ENTRY |
| ENDBR |
| pop %rcx |
| pop %r11 |
| jmp \name |
| SYM_CODE_END(xen_\name) |
| _ASM_NOKPROBE(xen_\name) |
| .endm |
| |
| xen_pv_trap asm_exc_divide_error |
| xen_pv_trap asm_xenpv_exc_debug |
| xen_pv_trap asm_exc_int3 |
| xen_pv_trap asm_xenpv_exc_nmi |
| xen_pv_trap asm_exc_overflow |
| xen_pv_trap asm_exc_bounds |
| xen_pv_trap asm_exc_invalid_op |
| xen_pv_trap asm_exc_device_not_available |
| xen_pv_trap asm_xenpv_exc_double_fault |
| xen_pv_trap asm_exc_coproc_segment_overrun |
| xen_pv_trap asm_exc_invalid_tss |
| xen_pv_trap asm_exc_segment_not_present |
| xen_pv_trap asm_exc_stack_segment |
| xen_pv_trap asm_exc_general_protection |
| xen_pv_trap asm_exc_page_fault |
| xen_pv_trap asm_exc_spurious_interrupt_bug |
| xen_pv_trap asm_exc_coprocessor_error |
| xen_pv_trap asm_exc_alignment_check |
| #ifdef CONFIG_X86_KERNEL_IBT |
| xen_pv_trap asm_exc_control_protection |
| #endif |
| #ifdef CONFIG_X86_MCE |
| xen_pv_trap asm_xenpv_exc_machine_check |
| #endif /* CONFIG_X86_MCE */ |
| xen_pv_trap asm_exc_simd_coprocessor_error |
| #ifdef CONFIG_IA32_EMULATION |
| xen_pv_trap asm_int80_emulation |
| #endif |
| xen_pv_trap asm_exc_xen_unknown_trap |
| xen_pv_trap asm_exc_xen_hypervisor_callback |
| |
| __INIT |
| SYM_CODE_START(xen_early_idt_handler_array) |
| i = 0 |
| .rept NUM_EXCEPTION_VECTORS |
| UNWIND_HINT_EMPTY |
| ENDBR |
| pop %rcx |
| pop %r11 |
| jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE |
| i = i + 1 |
| .fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc |
| .endr |
| SYM_CODE_END(xen_early_idt_handler_array) |
| __FINIT |
| |
| hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32 |
| /* |
| * Xen64 iret frame: |
| * |
| * ss |
| * rsp |
| * rflags |
| * cs |
| * rip <-- standard iret frame |
| * |
| * flags |
| * |
| * rcx } |
| * r11 }<-- pushed by hypercall page |
| * rsp->rax } |
| */ |
| SYM_CODE_START(xen_iret) |
| UNWIND_HINT_EMPTY |
| ANNOTATE_NOENDBR |
| pushq $0 |
| jmp hypercall_iret |
| SYM_CODE_END(xen_iret) |
| |
| /* |
| * XEN pv doesn't use trampoline stack, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is |
| * also the kernel stack. Reusing swapgs_restore_regs_and_return_to_usermode() |
| * in XEN pv would cause %rsp to move up to the top of the kernel stack and |
| * leave the IRET frame below %rsp, which is dangerous to be corrupted if #NMI |
| * interrupts. And swapgs_restore_regs_and_return_to_usermode() pushing the IRET |
| * frame at the same address is useless. |
| */ |
| SYM_CODE_START(xenpv_restore_regs_and_return_to_usermode) |
| UNWIND_HINT_REGS |
| POP_REGS |
| |
| /* stackleak_erase() can work safely on the kernel stack. */ |
| STACKLEAK_ERASE_NOCLOBBER |
| |
| addq $8, %rsp /* skip regs->orig_ax */ |
| jmp xen_iret |
| SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode) |
| |
| /* |
| * Xen handles syscall callbacks much like ordinary exceptions, which |
| * means we have: |
| * - kernel gs |
| * - kernel rsp |
| * - an iret-like stack frame on the stack (including rcx and r11): |
| * ss |
| * rsp |
| * rflags |
| * cs |
| * rip |
| * r11 |
| * rsp->rcx |
| */ |
| |
| /* Normal 64-bit system call target */ |
| SYM_CODE_START(xen_entry_SYSCALL_64) |
| UNWIND_HINT_ENTRY |
| ENDBR |
| popq %rcx |
| popq %r11 |
| |
| /* |
| * Neither Xen nor the kernel really knows what the old SS and |
| * CS were. The kernel expects __USER_DS and __USER_CS, so |
| * report those values even though Xen will guess its own values. |
| */ |
| movq $__USER_DS, 4*8(%rsp) |
| movq $__USER_CS, 1*8(%rsp) |
| |
| jmp entry_SYSCALL_64_after_hwframe |
| SYM_CODE_END(xen_entry_SYSCALL_64) |
| |
| #ifdef CONFIG_IA32_EMULATION |
| |
| /* 32-bit compat syscall target */ |
| SYM_CODE_START(xen_entry_SYSCALL_compat) |
| UNWIND_HINT_ENTRY |
| ENDBR |
| popq %rcx |
| popq %r11 |
| |
| /* |
| * Neither Xen nor the kernel really knows what the old SS and |
| * CS were. The kernel expects __USER32_DS and __USER32_CS, so |
| * report those values even though Xen will guess its own values. |
| */ |
| movq $__USER32_DS, 4*8(%rsp) |
| movq $__USER32_CS, 1*8(%rsp) |
| |
| jmp entry_SYSCALL_compat_after_hwframe |
| SYM_CODE_END(xen_entry_SYSCALL_compat) |
| |
| /* 32-bit compat sysenter target */ |
| SYM_CODE_START(xen_entry_SYSENTER_compat) |
| UNWIND_HINT_ENTRY |
| ENDBR |
| /* |
| * NB: Xen is polite and clears TF from EFLAGS for us. This means |
| * that we don't need to guard against single step exceptions here. |
| */ |
| popq %rcx |
| popq %r11 |
| |
| /* |
| * Neither Xen nor the kernel really knows what the old SS and |
| * CS were. The kernel expects __USER32_DS and __USER32_CS, so |
| * report those values even though Xen will guess its own values. |
| */ |
| movq $__USER32_DS, 4*8(%rsp) |
| movq $__USER32_CS, 1*8(%rsp) |
| |
| jmp entry_SYSENTER_compat_after_hwframe |
| SYM_CODE_END(xen_entry_SYSENTER_compat) |
| |
| #else /* !CONFIG_IA32_EMULATION */ |
| |
| SYM_CODE_START(xen_entry_SYSCALL_compat) |
| SYM_CODE_START(xen_entry_SYSENTER_compat) |
| UNWIND_HINT_ENTRY |
| ENDBR |
| lea 16(%rsp), %rsp /* strip %rcx, %r11 */ |
| mov $-ENOSYS, %rax |
| pushq $0 |
| jmp hypercall_iret |
| SYM_CODE_END(xen_entry_SYSENTER_compat) |
| SYM_CODE_END(xen_entry_SYSCALL_compat) |
| |
| #endif /* CONFIG_IA32_EMULATION */ |
